Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 25d9e2d1 authored by npiggin@suse.de's avatar npiggin@suse.de Committed by al
Browse files

truncate: new helpers 



Introduce new truncate helpers truncate_pagecache and inode_newsize_ok.
vmtruncate is also consolidated from mm/memory.c and mm/nommu.c and
into mm/truncate.c.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent eca6f534

Documentation/vm/locking

+1 −1
Original line number Diff line number Diff line
@@ -80,7 +80,7 @@ Note: PTL can also be used to guarantee that no new clones using the 
mm start up ... this is a loose form of stability on mm_users. For

example, it is used in copy_mm to protect against a racing tlb_gather_mmu

single address space optimization, so that the zap_page_range (from

vmtruncate) does not lose sending ipi's to cloned threads that might 

truncate) does not lose sending ipi's to cloned threads that might

be spawned underneath it and go to user mode to drag in pte's into tlbs.



swap_lock

fs/attr.c

+44 −2
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ 
/* Taken over from the old code... */



/* POSIX UID/GID verification for setting inode attributes. */

int inode_change_ok(struct inode *inode, struct iattr *attr)

int inode_change_ok(const struct inode *inode, struct iattr *attr)

{

	int retval = -EPERM;

	unsigned int ia_valid = attr->ia_valid;
@@ -60,9 +60,51 @@ int inode_change_ok(struct inode *inode, struct iattr *attr) 
error:

	return retval;

}



EXPORT_SYMBOL(inode_change_ok);



/**

 * inode_newsize_ok - may this inode be truncated to a given size

 * @inode:	the inode to be truncated

 * @offset:	the new size to assign to the inode

 * @Returns:	0 on success, -ve errno on failure

 *

 * inode_newsize_ok will check filesystem limits and ulimits to check that the

 * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ

 * when necessary. Caller must not proceed with inode size change if failure is

 * returned. @inode must be a file (not directory), with appropriate

 * permissions to allow truncate (inode_newsize_ok does NOT check these

 * conditions).

 *

 * inode_newsize_ok must be called with i_mutex held.

 */

int inode_newsize_ok(const struct inode *inode, loff_t offset)

{

	if (inode->i_size < offset) {

		unsigned long limit;



		limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;

		if (limit != RLIM_INFINITY && offset > limit)

			goto out_sig;

		if (offset > inode->i_sb->s_maxbytes)

			goto out_big;

	} else {

		/*

		 * truncation of in-use swapfiles is disallowed - it would

		 * cause subsequent swapout to scribble on the now-freed

		 * blocks.

		 */

		if (IS_SWAPFILE(inode))

			return -ETXTBSY;

	}



	return 0;

out_sig:

	send_sig(SIGXFSZ, current, 0);

out_big:

	return -EFBIG;

}

EXPORT_SYMBOL(inode_newsize_ok);



int inode_setattr(struct inode * inode, struct iattr * attr)

{

	unsigned int ia_valid = attr->ia_valid;

include/linux/fs.h

+2 −1
Original line number Diff line number Diff line
@@ -2382,7 +2382,8 @@ extern int buffer_migrate_page(struct address_space *, 
#define buffer_migrate_page NULL

#endif



extern int inode_change_ok(struct inode *, struct iattr *);

extern int inode_change_ok(const struct inode *, struct iattr *);

extern int inode_newsize_ok(const struct inode *, loff_t offset);

extern int __must_check inode_setattr(struct inode *, struct iattr *);



extern void file_update_time(struct file *file);

include/linux/mm.h

+3 −2
Original line number Diff line number Diff line
@@ -791,6 +791,7 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping, 
	unmap_mapping_range(mapping, holebegin, holelen, 0);

}



extern void truncate_pagecache(struct inode *inode, loff_t old, loff_t new);

extern int vmtruncate(struct inode *inode, loff_t offset);

extern int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end);

mm/filemap.c

+1 −1
Original line number Diff line number Diff line
@@ -58,7 +58,7 @@ 
/*

 * Lock ordering:

 *

 *  ->i_mmap_lock		(vmtruncate)

 *  ->i_mmap_lock		(truncate_pagecache)

 *    ->private_lock		(__free_pte->__set_page_dirty_buffers)

 *      ->swap_lock		(exclusive_swap_page, others)

 *        ->mapping->tree_lock